I. Field of the Invention
The present invention relates to fuel systems for automotive vehicles and, more particularly, to a capless fuel system for an automotive vehicle.
II. Description of Related Art
Automotive vehicles which utilize internal combustion engines necessarily require a fuel filling system. For many decades, the fuel filling system included a filler pipe connected to a fuel tank. The upper or inlet end of the fill tube was conventionally formed to accept a fuel cap which was removed only during fuel filling. A primary disadvantage of the system, however, is that the fuel caps not only became lost, but also added an additional cost to the automotive vehicle.
Consequently, capless fuel systems have been developed for automotive vehicles which eliminate the necessity of the fuel cap for closing the fuel fill tube. These previously known capless systems included a body which is generally cylindrical in shape and having an inlet end and an outlet end. The outlet end was connected to a fill tube which in turn was fluidly connected to the fuel tank. Conversely, the inlet end of the housing was dimensioned to receive a fuel nozzle for dispensing fuel through the housing, fill tube, and into the fuel tank. In order to prevent fuel fumes from escaping from the fuel tank, through the housing, and into the atmosphere, these previously known capless systems included a flapper valve which is fluidly connected in series between the inlet and the outlet of the housing. A spring urges the flapper valve against a valve seat contained within the housing in order to prevent the escape of fuel fumes into the atmosphere during the normal operation of the automotive vehicle. However, during a fuel filling operation, the fuel nozzle is inserted into the housing inlet and mechanically opens the flapper valve to permit fluid communication of the fuel from the fuel nozzle through the filler tube and into the fuel tank.
In certain situations, such as very hot weather, fuel fumes within the fuel tank may create an unacceptable high pressure of fuel fumes within the tank. Consequently, these previously known capless systems necessarily included a pressure relief valve formed in the housing. These pressure relief valves would open when the pressure within the fuel tank exceeded a predetermined pressure. Upon opening, the pressure relief valves would vent the fuel fumes.
The overall housing for the previously known fuel filling systems necessarily must be large enough to accommodate a flapper valve having a size sufficient to permit a standard fuel filling nozzle from a fuel pump to not only mechanically open the flapper valve, but also to extend through the port associated with the flapper valve. These fuel relief valves were then also contained within the housing at a position spaced radially outwardly from the flapper valve. While the system worked adequately to vent excess pressure from the fuel tank to the atmosphere, the positioning of the previously known pressure relief valves necessarily increased the overall size of the housing for the fuel filling system. This in turn increased not only the material cost for the fuel filling system, but also the space requirements in the vehicle for the fuel filling system.
A still further disadvantage of the previously known capless systems is that the flapper valve contained within the housing of the capless system would occasionally get stuck in between the insert provided around a standard fuel filling nozzle and the nozzle itself. When this occurred, the fuel filling nozzle could become “stuck” within the housing of the fuel filling system. When this occurred, the vehicle would be temporarily attached to the fuel pump.
A still further disadvantage of the previously known fuel filling systems, including capless systems, is that air is necessarily entrained within the fuel flow from the nozzle and into the fuel fill pipe. This entrained air, in turn, creates fuel fumes and these fuel fumes are then entrapped within carbon canisters contained within the fuel system of the vehicle. During the operation of the internal combustion engine, the fuel fumes from the carbon canisters are returned to the fuel system for combustion in the engine.
The standard carbon canisters used with fuel systems work adequately with automotive vehicles that are powered by internal combustion engines. However, hybrid vehicles utilize operation of an internal combustion engine only a short time during the overall operation of the automotive vehicle. The rather short time of operation of the internal combustion engine of a hybrid vehicle has proven insufficient to adequately return the fuel fumes stored in the fuel refill system carbon canisters to the fuel system for combustion.
A still further disadvantage of the previously known fuel filling system resides in the possibility of incorrectly filling a fuel tank of an automotive vehicle having a gasoline powered internal combustion engine with diesel fuel. The standard fuel filling nozzle for diesel fuel is smaller in diameter than the standard fuel filling nozzle for gasoline. Consequently, it has been possible to simply insert the diesel fuel filling nozzle into the fuel filling system and fill the fuel tank with diesel fuel. Subsequent operation of the internal combustion engine, however, will result in significant damage or even destruction of the internal combustion engine.